# CVE-2025-38231: nfsd: Initialize ssc before laundromat_work to prevent NULL dereference

Status: published. Published: 2025-07-04. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

nfsd: Initialize ssc before laundromat_work to prevent NULL dereference

In nfs4_state_start_net(), laundromat_work may access nfsd_ssc through
nfs4_laundromat -> nfsd4_ssc_expire_umount. If nfsd_ssc isn't initialized,
this can cause NULL pointer dereference.

Normally the delayed start of laundromat_work allows sufficient time for
nfsd_ssc initialization to complete. However, when the kernel waits too
long for userspace responses (e.g. in nfs4_state_start_net ->
nfsd4_end_grace -> nfsd4_record_grace_done -> nfsd4_cld_grace_done ->
cld_pipe_upcall -> __cld_pipe_upcall -> wait_for_completion path), the
delayed work may start before nfsd_ssc initialization finishes.

Fix this by moving nfsd_ssc initialization before starting laundromat_work.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ a4bc287943f5695209ff36bdc89f17b48d68fae7; < deaeb74ae9318252829c59a84a7d2316fc335660 (affected, git); ≥ f4e44b393389c77958f7c58bf4415032b4cda15b; < 0fccf5f01ed28725cc313a66ca1247eef911d55e (affected, git); ≥ f4e44b393389c77958f7c58bf4415032b4cda15b; < a97668ec6d73dab237cd1c15efe012a10090a4ed (affected, git); ≥ f4e44b393389c77958f7c58bf4415032b4cda15b; < 5060e1a5fef184bd11d298e3f0ee920d96a23236 (affected, git); ≥ f4e44b393389c77958f7c58bf4415032b4cda15b; < d622c2ee6c08147ab8c9b9e37d93b6e95d3258e0 (affected, git); ≥ f4e44b393389c77958f7c58bf4415032b4cda15b; < 83ac1ba8ca102ab5c0ed4351f8ac6e74ac4d5d64 (affected, git); ≥ f4e44b393389c77958f7c58bf4415032b4cda15b; < b31da62889e6d610114d81dc7a6edbcaa503fcf8 (affected, git); ≥ 5.10.220; < 5.10.239 (affected, semver). Source: CNA: Linux
- Linux / Linux: 5.14 (affected); ≥ 0; < 5.14 (unaffected, semver); ≥ 5.10.239; ≤ 5.10.* (unaffected, semver); ≥ 5.15.186; ≤ 5.15.* (unaffected, semver); ≥ 6.1.142; ≤ 6.1.* (unaffected, semver); ≥ 6.6.95; ≤ 6.6.* (unaffected, semver); ≥ 6.12.35; ≤ 6.12.* (unaffected, semver); ≥ 6.15.4; ≤ 6.15.* (unaffected, semver); ≥ 6.16; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-05; percentile 8.10%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/deaeb74ae9318252829c59a84a7d2316fc335660 (CNA: Linux)

- https://git.kernel.org/stable/c/0fccf5f01ed28725cc313a66ca1247eef911d55e (CNA: Linux)

- https://git.kernel.org/stable/c/a97668ec6d73dab237cd1c15efe012a10090a4ed (CNA: Linux)

- https://git.kernel.org/stable/c/5060e1a5fef184bd11d298e3f0ee920d96a23236 (CNA: Linux)

- https://git.kernel.org/stable/c/d622c2ee6c08147ab8c9b9e37d93b6e95d3258e0 (CNA: Linux)

- https://git.kernel.org/stable/c/83ac1ba8ca102ab5c0ed4351f8ac6e74ac4d5d64 (CNA: Linux)

- https://git.kernel.org/stable/c/b31da62889e6d610114d81dc7a6edbcaa503fcf8 (CNA: Linux)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (ADP: CVE)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html (ADP: CVE)

- https://cert-portal.siemens.com/productcert/html/ssa-082556.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2025-38231; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-38231; retrieved 2026-11-05; source updated Not reported

Revision: 67714b80347ddc35d8fcf459f64ccfaed0fb456c3a6f02ff8de7e5cea8ac65b3

Canonical: https://y2.dev/cve/CVE-2025-38231

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